Constructive criticism (often shortened to 'CC' or 'concrit') is the process of offering valid and well-reasoned opinions about the work of others, usually involving both positive and negative comments, in a friendly manner rather than an oppositional one. In collaborative work, this kind of criticism is often a valuable tool in raising and maintaining performance standards.
If you want to read more on it;
Code:
http://en.wikipedia.org/wiki/Constructive_criticism
When you post reviews and comments about ones work:
Do not post any negative comments towards the user
As stated about, Comments should be expressed in a friendly matter, meaning things like "Its sucks," does not count.
Also, "Thats horrible," does not count either, you have to give a reason for your comments, and tips on what the user can do to improve on his work. The point is to help the user, not degrade them.
We can tell the difference between a concrit and a flame response, so dont try to tell us otherwise.
Remember, you guys asked for this, so dont spoil it with pointless comments. THINK BEFORE YOU POST!
And thats about it,
bbz